No particular theory may ever be regarded as absolutely certain.... No scientific theory is sacrosanct.
Interpretation
Scientific theories are provisional and subject to change rather than being seen as absolute truths.
In this quote, Karl Popper emphasizes the idea that scientific theories should not be considered as definitive truths. Instead, they are always open to questioning, revision, and falsification. This notion highlights the dynamic and evolving nature of scientific inquiry, suggesting that the pursuit of knowledge is an ongoing process rather than a conclusion to be firmly established.
In practice
In a science class discussing the nature of scientific theories.
The growth of our knowledge is the result of a process closely resembling what Darwin called 'natural selection'; that is, the natural selection of hypotheses: our knowledge consists, at every moment, of those hypotheses which have shown their (comparative) fitness by surviving so far in their struggle for existence, a competitive struggle which eliminates those hypotheses which are unfit.
If you can't say it simply and clearly, keep quiet, and keep working on it till you can.
The belief in a political Utopia is especially dangerous. This is possibly connected with the fact that the search for a better world, like the investigation of our environment, is (if I am correct) one of the oldest and most important of all the instincts.
A rationalist is simply someone for whom it is more important to learn than to be proved right; someone who is willing to learn from others - not by simply taking over another's opinions, but by gladly allowing others to criticize his ideas and by gladly criticizing the ideas of others
Thus science must begin with myths, and with the criticism of myths; neither with the collection of observations, nor with the invention of experiments, but with the critical discussion of myths, and of magical techniques and practices.
I am opposed to looking upon logic as a kind of game. ... One might think that it is a matter of choice or convention which logic one adopts. I disagree with this view.
True science discovers God in an ever-increasing degree β as though God were waiting behind every door opened by science.
From the rocket we can see the huge sphere of the planet in one or another phase of the Moon. We can see how the sphere rotates, and how within a few hours it shows all its sides successively ... and we shall observe various points on the surface of the Earth for several minutes and from different sides very closely. This picture is so majestic, attractive and infinitely varied that I wish with all my soul that you and I could see it.
The aim of scientific thought, then, is to apply past experience to new circumstances; the instrument is an observed uniformity in the course of events. By the use of this instrument it gives us information transcending our experience, it enables us to infer things that we have not seen from things that we have seen; and the evidence for the truth of that information depends on our supposing that the uniformity holds good beyond our experience.
You can prove anything you want by coldly logical reason---if you pick the proper postulates.
Population, when unchecked, increases in a geometrical ratio.
It is hard to overstate how valuable it is to have all the incredible tools that are used for human disease to study plants.
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